Acute toxicity of commonly used forestry herbicide mixtures to Ceriodaphnia dubia and Pimephales promelas

Because many herbicides selectively control specific species or types of vegetation, they are often applied as mixtures to achieve better control over undesirable vegetation. When herbicides are applied in forest ecosystems, streams, ponds, and other bodies of water are typically protected by buffer zones in which no herbicide is applied. However, in some landscapes, small wetlands and streams are difficult to see and avoid, thus the potential acute toxicity of herbicide mixtures to aquatic organisms is of interest, yet it has not been well‐studied. We examined the acute toxicity of 23 different herbicide mixtures to Ceriodaphnia dubia and fathead minnows (Pimephales promelas) at environmentally relevant concentrations, and, where possible, characterized mixture interactions using Marking's Additive Index. Maximum exposure concentrations were equivalent to applying the maximum allowable rate for each component directly to the surface of a 6‐in. deep pond with no dissipation following application. Under the conditions of this study, herbicide formulations containing Accord Concentrate (glyphosate), Arsenal AC (imazapyr), Chopper (imazapyr), Escort (metsulfuron methyl), Oust XP (sulfometuron methyl), and Velpar L (hexazinone) were not associated with appreciable acute toxicity to fathead minnows or C. dubia when used alone or in mixtures with each other and various surfactants and adjuvants. Herbicide mixtures for which Additive Indexes could be calculated exhibited primarily antagonistic or simple additive toxicity. In the few cases where synergistic toxicity was observed, the degree of synergism was slight, never exceeding approximately twice the effect estimated based on additive toxicity. Based on the results of this study, neither acute toxicity nor enhanced acute aquatic toxicity due to synergistic mixture effects appears to be a significant concern for applications of the herbicide mixtures most commonly used in forestry. © 2011 Wiley Periodicals, Inc. Environ Toxicol 2012.     

Hazard assessment of commonly used agricultural antibiotics on aquatic ecosystems

In this study, eleven commonly used antibiotics including sulfonamides, tetracyclines, aminoglycosides, fluoroquinolones, and beta-lactams were evaluated for their acute and chronic aquatic toxicities using standard test organisms e.g., Vibrio fischeri, Daphnia magna, Moina macrocopa, and Oryzias latipes. Among the antibiotics tested for acute toxicity, neomycin was most toxic followed by trimethoprim, sulfamethoxazole and enrofloxacin. Sulfamethazine, oxytetracycline, chlortetracycline, sulfadimethoxine and sulfathiazole were of intermediate toxicity, while ampicillin and amoxicillin were least toxic to the test organisms. There were no trends in sensitivity among test organisms or among different classes of the antibiotics. Only the beta-lactam class was the least toxic. In chronic toxicity test, neomycin affected reproduction and adult survival of D. magna and M. macrocopa with low mg/l levels exposure. Predicted no effect concentrations (PNECs) were derived from the acute and chronic toxicity information gleaned from this study and from literature. When the PNECs were compared with measured environmental concentrations (MECs) reported elsewhere for the test compounds, hazard quotients for sulfamethoxazole, sulfathiazole, chlortetracycline, oxytetracycline, and amoxicillin exceeded unity, which suggests potential ecological implication. Therefore, further studies including monitoring and detailed toxicological studies are required to assess potential ecological risk of these frequently used veterinary antibiotics.     

Liver toxicity mechanisms of herbs commonly used in Latin America

Mexico owns approximately 4500 medicinal plants species, a great diversity that position it at the second place after China. According to the Mexican health department, 90% of common population consumes them to treat various diseases. Additionally, herbal remedies in Latin America (LA) are considered a common practice, but the frequency of use and the liver damage related to its consumption is still unknown. Despite the high prevalence and indiscriminate herbal consumption, the exact mechanism of hepatotoxicity and adverse effects is not fully clarified and is still questioned. Some herb products associated with herb induced liver injury (HILI) are characterized by presenting a different chemical composition that may vary from batch to batch, also the biological activity of many medicinal plants and other natural products are directly related to their most active component and its concentration. There are two main biological components that are associated with liver damage, alkaloids, and flavonoids, which are frequent constituents of commonly used herbs. The interaction with the different cytochrome P-450 isoforms, inflammatory, and oxidative activities seem to be the main damage pathway involved in the liver. It is important to know the herbal adverse effects and mechanisms involved; therefore, this article is focused on the beneficial and deleterious effects as well as the possible toxicity mechanisms and interactions of the herbs that are frequently used in LA, since the herb–host interaction may not always be the expected or desired depending on the clinical context in which it is administered.     

Lack of toxicity and carcinogenicity of some commonly used cutaneous agents

The potential carcinogenicity and toxicity of several commonly used cutaneous agents (benzophenone, propylene glycol, isopropyl myristate, resorcinol, 2-ethyl-1,3-hexanediol, p-aminobenzoic acid and pyrogallol) were studied in female Swiss mice by administering repeated applications of the chemicals on the skin for the life-span of the animals. Tumors seen in both control and treated animals were mainly lymphomas, hemangiomas of the liver and lung adenomas, as well as tumors of other organs. A statistically significant increase in tumor incidence caused by the chemical treatment was not seen. Skin lesions, slight inflammation and ulceration were seen, but no persistent cutaneous abnormalities occurred. A few skin tumors were seen in treated areas as well as in untreated areas and in control animals. Thus a carcinogenic or toxic potential which would affect the use of these agents in man was not detected.     

In vitro studies of cellular and molecular developmental toxicity of adjuvants, herbicides, and fungicides commonly used in Red River Valley, Minnesota

Recent epidemiologic studies showed increased frequency of birth defects in pesticide applicators and general population of the Red River Valley, Minnesota. These studies further indicated that this crop growing area used more chlorophenoxy herbicides and fungicides than elsewhere in Minnesota. Based on frequency of use and known biology, certain herbicides, pesticide additives, fungicides, and mycotoxins are suspect agents. To define whether these agents affect developmental endpoints in vitro, 16 selected agrochemicals were examined using the MCF-7 breast cancer cell line. In the flow cytometric assay, cell proliferation in this estrogen-responsive cell line indicates xenobiotic-mediated estrogenic effects. Cell viability, morphology, ploidy, and apoptosis were incorporated in this assay. Data showed that the adjuvants X-77 and Activate Plus induced significant cell proliferation at 0.1 and 1 microg/ml. The commercial-grade herbicides 2,4-D LV4 and 2,4-D amine induced cell proliferation at 1 and 10 microg/ml. The reagent-grade 2,4-D products failed to induce proliferation over the same concentration range, suggesting that other ingredients in the commercial products, presumably adjuvants, could be a factor in these results. The fungicides triphenyltin and mancozeb induced apoptosis at concentrations of 4.1 microg/ml (10(-5) M) and 50 microg/ml, respectively. Triphenyltin also induced aneuploidy (C2/M arrest) at 0.41 microg/ml (10(-6) M). Data provide a mechanistic step to understanding human reproductive and developmental effects in populations exposed to these agrochemicals, and initiative to focusing limited resources for future in vivo animal developmental toxicity studies.     

治疗肩锁关节脱位的两种常用方法的疗效分析

目的探讨锁骨钩和克氏针治疗肩锁关节脱位的效果。方法对38例肩锁关节脱位的患者分别进行锁骨钩内固定和克氏针内固定。术后按照Karlsson的评分标准,对患者进行优、良、差的评价,并比较两种治疗方法在住院时间、脱位愈合时间方面的差异。结果按照Karlsson的评分标准,锁骨钩组的优良率为95.24%,而克氏针组的为71.43%,两者比较有统计学意义(P<0.05);锁骨钩组在住院时间和愈合时间方面明显优于克氏针组,两组比较有统计学意义(P<0.05)。结论锁骨钩钢板固定可靠,可以早期进行功能锻炼,是治疗完全性肩锁关节脱位的一种可靠的方法,值得推荐。     

Response characteristics of an aquatic biomonitor used for rapid toxicity detection

The response characteristics of an aquatic biomonitor that detects toxicity by monitoring changes in bluegill (Lepomis macrochirus Rafinesque) ventilatory and movement patterns were evaluated in single chemical laboratory studies at concentrations near the 96-h LC(50) concentration and at the EILATox-Oregon Workshop in sequential tests of multiple unknown samples. Baseline data collected prior to exposure allows each fish to serve as its own control. When at least 70% of exposed fish exhibit ventilatory or movement parameters significantly different from baseline observations, a group alarm is declared. In the laboratory studies, the aquatic biomonitor responded to the majority of chemicals at the 96-h lc(50) within an hour or less, although substantially higher response times were found for malathion and pentachlorophenol. Workshop tests of single chemical concentrations presented as blind samples were consistent with the laboratory test results. There were no alarms under control conditions in any test. Although data are limited, the aquatic biomonitor appears to respond more rapidly to chemicals causing membrane irritation, narcosis or polar narcosis than to acetylcholinesterase inhibitors or oxidative phosphorylation uncouplers. All four monitored parameters (ventilatory rate, cough rate, ventilatory depth and movement) contributed to identification of first alarms at acutely toxic levels. Understanding these response patterns can be useful in data interpretation for biomonitor applications such as surface water monitoring for watershed protection, wastewater treatment plant effluent monitoring or source water monitoring for drinking water protection.     

Comparison of embryo toxicity using two classes of aquatic vertebrates

Toxicity tests of musk ketone (MK) and tetrabromobisphenol-A (TBBPA) on embryos were conducted in two amphibian species, Xenopus (Silurana) tropicalis and the Swedish native species Rana arvalis. TBBPA was also tested on fish embryos of Danio rerio. All species were tested in similar experimental setup. Musk ketone caused decreased heart rates at concentrations from 10 and 100 μg/L in R. arvalis and X. tropicalis, respectively. TBBPA caused effects at 1000 μg/L in all three species. The responses were comparable between all three species which supports the relevance for using data from non-native species in national risk assessment.     

Neurobehavioral development of two mouse lines commonly used in transgenic studies

The present study was aimed at establishing the differences in the neurodevelopmental profile between two F2 lines derived from two F1 hybrid mouse strains (129 x C57BL/6 and C57BL/6 x SJL). The choice of the given strains was based on the frequent use of these mice in transgenic research. For the neurodevelopment phenotyping, we employed a test battery consisting of 23 somatometric, sensorial and motor tests. Significant variations between the strains were established in different functional domains. Some specific delays in the appearance of developmental landmarks were observed in F2 mice derived from crosses of F1 C57BL/6 x 129, whereas they acquired early developmental functions, such as the righting reflex, sooner than C57BL/6 x SJL-derived mice. C57BL/6 x 129 F2 offspring were spontaneously hypoactive, and their poorer motor performance was confirmed by low performance in the negative geotaxis test. However, there were no differences in the general psychomotor development as shown by the good performance in the homing test in both F2 lines. Both strains were susceptible to the handling procedures used, presenting a similar alteration in the response observed in the homing test as compared to nonhandled control mice. In conclusion, our work highlights the importance of the genetic background for transgenesis experiments and also the need for well-established testing protocols to obtain sufficient information at the first stage of behavioral screening of genetically modified mice.     

两种卡铂注射液与输液的配伍稳定性考察

目的：考察两种卡铂注射液与输液的配伍稳定性。方法：将两种卡铂注射液分别使用0.9%氯化钠、5%葡萄糖溶液稀释,分别在25℃和42℃下于0,2,4,6,8,12,24 h时观察配伍液的外观变化,测定其pH值,采用高效液相色谱法测定配伍液中卡铂的相对百分含量。结果：在上述条件下,配伍液在24 h内外观和pH值均无明显变化;齐鲁卡铂各时间点、各配伍液中卡铂的相对百分含量为94.55%~100.64%,RSD<2%;施贵宝卡铂各时间点、各配伍液中卡铂的相对百分含量为91.55%~100.37%,RSD<3%。结论：两种卡铂注射液与0.9%氯化钠注射液、5%葡萄糖注射液配伍后,在25℃和42℃条件下,24 h内稳定,在葡萄糖中稳定性更好。     

Acute toxicity of sodium selenate to two daphnids and three amphipods

This study evaluated the acute toxicity of sodium selenate to two daphnid and three gammarid amphipod species. The daphnids, Ceriodaphnia dubia and Daphnia pulex, were evaluated in 48-hour static tests and the amphipods, Gammarus pseudolimnaeus, Gammarus lacustris, and Hyalella azteca, were evaluated in 96-hour static and flow-through tests. Tests resulted in mean LC50's of 1.92, 9.12, 1.82, 3.05, and 1.95 mg/L selenium for C. dubia, D. pulex, G. pseudolimnaeus, G. lacustris, and H. azteca, respectively. The LC50's for the G. pseudolimnaeus tests are more than 30-fold higher than previously reported LC50's for the same or similar species. The explanation for these differing results appears to be partially, but not entirely, explained by differences in ambient pH between the new studies and previous ones. Depending on how the new data are included in U.S. EPA's selenium freshwater quality criterion data set, the selenate acute water quality criterion (i.e., Criterion Maximum Concentration) increases from 12.8 to as high as 583 microg/L selenium.     

内科常用药物相关的急性肾衰竭

药源性急性肾衰竭（DARF）是指药物引起的以急性水、电解质紊乱和酸碱平衡失调及氮质血症为主要特征的一组临床综合征。DARF是一种常见的药源性疾病，约占肾实质性急性肾衰竭的19％～40％。其临床特点是在用药数日或数周内出现少尿或非少尿型ARF，部分患者可同时出现药疹、药物热、贫血、肝功能损害、神经系统损害等表现。DARF最常见的临床病理类型有急性肾小管坏死、急性间质性肾炎。DARF的发病机制主要为药物引起肾血流动力学改变导致肾灌注量减少、对肾小管细胞的毒性作用导致急性肾小管坏死、免疫反应导致急性间质性肾炎、药物结晶沉积导致管腔阻塞或免疫介导的肾小球肾炎等。DARF的相关危险因素包括药物的肾毒性作用、剂量、疗程，以及患者的机体状态如：高龄、血容量不足、糖尿病、既往肾损害或肾功能不全等。DARF的常见致病药物有抗生素、非甾体抗炎药、利尿剂及某些中药等。本文重点介绍内科常用的心血管系统药物、消化系统药物及抗病毒药导致DARF的临床特点及其防治。     

药动学研究常用软件介绍

药动学是一门研究药物体内动态变化规律及其影响因素的学科。药动学模型研究从经典的房室模型,统计矩理论的应用,到复杂的群体药动学、生理药动学以及药动-药效学建模,都需要可靠的软件工具来完成复杂的数学计算过程。一些商业公司开发的药动学模型专业软件,已在药物研发和科学研究中广为应用;另一方面,开源工具正得到大力推广。本文总结目前用于药动学模型研究的主流软件工具,对其功能应用做简要介绍,以期为国内相关研究者提供有价值的信息。     

常用他汀类药物的比较研究

他汀类药物是治疗高胆固醇血症的一线药物,也是心脑血管病一级和二级预防的最重要药物之一。不同他汀类药物在药动学、药效学方面存在差异,其不良反应对患者的健康也会产生一定的影响。本文总结了国内常用7种他汀类药物在药动学、临床应用、安全性方面的异同,以期为临床医师选择合适的降脂措施,降低不良反应发生率,提供参考。     

Acute aquatic toxicity of tire and road wear particles to alga,daphnid, and fish

Previous studies have indicated that tire tread particles are toxic to aquatic species, but few studies have evaluated the toxicity of such particles using sediment, the likely reservoir of tire wear particles in the environment. In this study, the acute toxicity of tire and road wear particles (TRWP) was assessed in Pseudokirchneriella subcapita, Daphnia magna, and Pimephales promelas using a sediment elutriate (100, 500, 1000 or 10000 mg/l TRWP). Under standard test temperature conditions, no concentration response was observed and EC/LC₅₀ values were greater than 10,000 mg/l. Additional tests using D. magna were performed both with and without sediment in elutriates collected under heated conditions designed to promote the release of chemicals from the rubber matrix to understand what environmental factors may influence the toxicity of TRWP. Toxicity was only observed for elutriates generated from TRWP leached under high-temperature conditions and the lowest EC/LC₅₀ value was 5,000 mg/l. In an effort to identify potential toxic chemical constituent(s) in the heated leachates, toxicity identification evaluation (TIE) studies and chemical analysis of the leachate were conducted. The TIE coupled with chemical analysis (liquid chromatography/mass spectrometry/mass spectrometry [LC/MS/MS] and inductively coupled plasma/mass spectrometry [ICP/MS]) of the leachate identified zinc and aniline as candidate toxicants. However, based on the high EC/LC₅₀ values and the limited conditions under which toxicity was observed, TRWP should be considered a low risk to aquatic ecosystems under acute exposure scenarios.     

深部感染真菌对常用抗真菌药物的耐药性

目的:调查北京医院2003年4月～10月期间真菌感染的菌种分布及耐药性,指导临床合理用药.方法:采用显色培养基对真菌进行鉴定,用药敏纸片法测定真菌对氟康唑、伊曲康唑和两性霉素B的敏感性.结果:共分离到285株真菌,主要来源于呼吸道、泌尿道和消化道,其中检出最多的是白色假丝酵母133株(46.7%)、光滑假丝酵母66株(23.2%)和热带假丝酵母54株(18.9%).三种抗真菌药物对285株深部感染真菌总的耐药率分别为氟康唑10.9%、伊曲康唑7.7%和两性霉素B0%.对氟康唑耐药的有光滑假丝酵母26株、克柔假丝酵母1株、季也蒙假丝酵母2株和白色假丝酵母2株;对伊曲康唑耐药性较高有克柔假丝酵母1株、季也蒙假丝酵母2株、热带假丝酵母5株、光滑假丝酵母12株和白色假丝酵母2株.结论:定期开展真菌的耐药监测,有助于合理应用抗真菌药物.